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Biomedical subjects

H Kawamura

Publications and source records attributed to H Kawamura.

At least 343 records · Page 19Linked to original sources
PubMed1988

[Identification of location of electrode tip during percutaneous retrogasserian glycerol injection (PRGI) with blink reflexes elicited by direct stimulation of trigeminal complex (DBR)].

In order to identify the location of the electrode tip during percutaneous retrogasserian glycerol injection (PRGI), the blink reflex (DBR) following direct stimulation of the trigeminal complex (the gasserian ganglion, trigeminal rootlets, or the 3rd division of the trigeminal nerve) was obtained from 6 patients with trigeminal neuralgia. 1) The waveform of the DBR was very similar to that of the blink reflex (BR) elicited by percutaneous stimulation of the 1st division of the trigeminal nerve. However, the latency of early reflex (R1) as well as late reflex (R2) of the DBR was approximately 2 msec shorter than that of the conventional BR. 2) When the electrode tip was introduced into the gasserian ganglion, the DBR showed the largest response under the same recording condition, whereas the DBR was not recorded when the tip of the electrode was placed into either the arachnoid space or the subdural space. The each DBR response, however, showed the same configuration when the electrode tip was situated at the territory of the 1st, 2nd or 3rd division of the trigeminal nerve within the gasserian ganglion or the trigeminal cistern. 3) The DBR always appeared under the anesthesia with the intravenous administration of 10 mg diazepam and 30 mg pentazocine. 4) Based on the present study, the DBR proved to be an usuful parameter in determining whether the electrode tip is introduced into the trigeminal complex or not, particularly in the case of patients having no reliable sensory response to electrical stimulation.

Aged↗
PubMed1988

[Post-treatment changes of skeletal Class III morphology operated by orthognathic two-jaw surgery].

The purpose of this study was to investigate the dentofacial changes following orthognathic Two-jaw surgery in skeletal Class III patients. The materials consisted of cephalometric head films of 20 patients who had simultaneously undergone Le Fort I osteotomy and mandibular ramus osteotomy. All cases received the pre- and post-operative orthodontic treatment and had the observation periods over than one year after postoperative orthodontic treatment. The cephalometric radiographs were taken at following five stages: 1. Before preoperative orthodontic treatment, 2. Immediately before surgery, 3. After intermaxillary fixation, 4. After postoperative orthodontic treatment, and 5. Posttreatment observation period. The results were as follows: 1. The anteroposterior skeletal relapse was minimum after surgery. 2. The surgical manner of the maxillary vertical displacement did not effect the stability of the upper facial height after surgery. The lower facial height tended to decrease slightly during postoperative orthodontic treatment. 3. The upper and lower incisors showed lingual tipping during intermaxillary fixation, but the upper incisors tipped labially during retention period. In conclusions, Two-jaw surgery was considered to be quite effective for the correction of skeletal Class III malocclusions especially with the maxillary deficiency.

Humans↗
PubMed1987

Characterization of rat c-myc and adjacent regions.

Rat genomic regions covering c-myc were cloned from the DNA of both normal liver and two lines of Morris hepatomas, one of which had c-myc amplification. The three restriction maps showed perfect agreement within the overlapping regions. The 7 kb regions, which included the entire normal rat c-myc and the region 2.2 kb upstream, and one from the hepatomas, were sequenced and found to be identical. The coding regions of exons 2 and 3 were highly conserved between rat, mouse and man, but some differences in amino acids were noted. Exon 1 and the non-coding region of exon 3 showed limited homology between the three species. Rat exon 1 contained several nonsense codons in each frame and no ATG codon, indicating there to be no coding capacity in this exon. The 2.2 kb upstream regions and the introns compared showed unusual conservation between the rat and human genes. Some motifs, previously proposed as having a functional role in human c-myc, were also found in equivalent positions of the rat sequence. Nucleas S1 protection mapping revealed the second promoter to be preferentially used in most tissues or in hepatoma cells, and the second poly A addition signal to be the only one functional in all the RNA sources examined.

Amino Acid Sequence↗
PubMed1987

Cloned protein antigen-specific, Ia-restricted T cells with both helper and cytolytic activities: mechanisms of activation and killing.

Myoglobin-specific, Iad-restricted cloned helper T cells and T hybridomas were found to directly kill Iad-bearing, myoglobin-pulsed B lymphoma targets and could also kill bystander targets, but only in the presence of antigen-pulsed antigen presenting cells (APC). The induction of the killing requires recognition of processed antigen in the context of class II major histocompatibility complex (MHC) molecules. Despite the specificity of induction, the bystander killing suggests a nonspecific lytic mechanism. The direct killing can be inhibited only by cold specific targets, whereas the bystander killing can be blocked by both specific and nonspecific targets. The cold target inhibition seems to be due to interference with effector-to-target contact or proximity rather than due to high-dose suppression of T-cell activation. Experiments using T-cell supernatants or cyclosporin A suggested that the helper T cells kill targets by synthesizing short-range soluble factor(s) with nonspecific killing activity de novo during the effector phase, but only while antigen-specific signal transduction is occurring. The mechanism of cold target inhibition appears to be absorption or consumption of a short-acting cytotoxic lymphokine by cells which must be able to interact closely with the effector cell. Normal spleen B cells, despite their capability for activating the helper T cells, cannot inhibit specific killing or be killed by helper T cells, even after lipopolysaccharide stimulation. Thus, although killing by helper T cells may play a negative feedback role in the normal immune response, our data raise the possibility that the helper T-cell-mediated killing may contribute to the immune surveillance against malignancy by virtue of the preferential killing of tumor cells either directly or indirectly.

Antigen-Presenting Cells↗
PubMed1987

Primary culture of epithelial cells derived from the rat ventral prostate: formation of three-dimensional acinus-like structure in collagen gel.

Rat ventral prostate epithelial cells were cultured in collagen gel after collagenase digestion. The primary cultures were mainly composed of single and spherical cells. After 10 days incubation in growth medium containing insulin, transferrin, and cholera toxin, there was a 3.8-fold increase in cell numbers, aggregates of which formed three-dimensional acinus-like structures. These structures consisted of one layer of cells surrounding the lumen. The cells were joined together with a junctional complex and had microvilli on the luminal surface and secretory vacuoles in the cytoplasm facing the lumen. The ultrastructural features of the cells were not altered by growth medium containing steroids. This culture system may prove to be very useful in elucidating proliferation, organization, and differentiation of prostatic epithelial cells in relation to the extracellular matrix and stromal cells.

Animals↗
PubMed1987

Surgical treatment of hypertensive intracerebral haematoma by CT-guided stereotactic surgery.

Ninety consecutive cases of hypertensive intracerebral haematoma were treated with CT guided stereotactic evacuation. The patients were composed of 61 males and 29 females, ranging from 42 to 87 years old. The location of haematoma was either in the putamen (59 cases) or in the thalamus (31 cases). The average volume of the evacuated haematoma was 21.4 ml in the putaminal haematoma and 14.0 ml in the thalamic haematoma. Postoperative follow-up study in 46 patients showed good recovery of neurological deficits both in putaminal and thalamic group. Criteria of surgical indication of CT-guided stereotactic evaluation of intracerebral haematoma were advocated based on the author's clinical experience.

Adult↗
PubMed1987

Short latency somatosensory-evoked potentials--direct recording from the human midbrain and thalamus.

Short latency somatosensory-evoked potentials were recorded from the human thalamus and the midbrain during stereotactic operations. Several subcomponents were recognized on the peak of N18. These were recorded with maximal amplitude at the border between the caudal portion of the thalamus and the rostral midbrain. Two positive-negative responses, not previously shown, were observed between P14 and N18. These responses were prominent in the rostral midbrain. These findings indicate that the ascending phase of N18, and the N18 itself, are the compound potential generated in the mesodiencephalic junction.

Brain Mapping↗